Boris Johnson is hoping to push his Brexit deal through Parliament, but first he needs Commons Speaker John Bercow to allow it.
The Prime Minister is hoping that it will not be a second defeat for him after Sir Oliver Letwin's amendment on Saturday forced him to request a Brexit extension from the EU - something he repeatedly said he would not do.
Should Mr Bercow allow the deal to be debated again and voted on in the Commons, after gauging support amongst MPs, it seems that they will try and add three crucial amendments to it.
In order of the threat they pose to Boris Johnson, they are:
Remove the No Deal "trapdoor" at end of transition period
This is the greatest threat because we might assume everyone who voted for the Letwin Amendment on Saturday will also vote for the trap door amendment, because both seek to remove the risk of a no-deal Brexit at the end of the transition period in December 2020.
But can the pro-Brexit European Research Group (ERG) support a deal which doesn’t allow no-deal at end of transition?
A customs union
This could be close-run, but at the moment seems ambitious.
Labour will back it, SNP might back it this time, some Labour rebels who back the PM’s deal will also back it, but previous Tory supporters appear to be peeling away and Lib Dems/DUP are unlikely to back it.
A second referendum
A second referendum seems the least likely of the three amendments to pass as things stand on Monday.
Another vote does not have enough support on Tory benches and the DUP won’t back it, but that doesn’t mean it won’t look like an option if either or the others pass and the PM’s deal begins to collapse.
What all three amendments illustrate is the sheer fragility of the coalition the PM has put together.
If any of them pass, he will lose the backing of the pro-Brexit European Research Group.
If the first amendment doesn’t pass or happen, the PM may lose MPs who won’t countenance no-deal.
This is why the Government didn’t want to get into the detail until a meaningful vote had passed.
Of course other amendments may emerge in the course of the week and support may shift and change once the Withdrawal Agreement Bill is published this evening and MPs see the detail.
But this is a snapshot of where we stand at the moment.